Table of Contents
Advertisement
www.ti.com
12.3.2 REG1 and REG2 LDO Controls
The REG1 and REG2 LDOs in the BQ76952 device are for customer use, and their output voltages can be
programmed independently to 1.8 V, 2.5 V, 3.0 V, 3.3 V, or 5.0 V. The REG1 and REG2 LDOs and the REG0
preregulator are disabled by default in the BQ76952 device. While in SHUTDOWN mode, the REG1 and REG2
pins have ≈10-MΩ resistances to VSS, to discharge any output capacitance. While in other power modes,
when REG1 and REG2 are powered down, they are pulled to VSS with an internal resistance of ≈2.5-kΩ. If
pullup resistors for serial communications are connected to the REG1 voltage output, the REG1 voltage can be
overdriven from an external voltage supply on the manufacturing line, to allow communications with the device.
The BQ76952 device can then be programmed to enable REG0 and REG1 with the desired configuration, and
this setting can be programmed into OTP memory. Thus, at each later power-up, the device will autonomously
load the OTP settings and enable the LDO as configured, without requiring communications first.
12.4 Standalone Versus Host Interface
The BQ76952 device can be configured to operate in a completely standalone mode, without any host processor
in the system, or together with a host processor. If in standalone mode, the device can monitor conditions,
control FETs and an in-line fuse based on threshold settings, and recover FETs when conditions allow, all
without requiring any interaction with an external processor. If a host processor is present, the device can still be
configured to operate fully autonomously, while the host processor can read measurements and exercise control
as desired. In addition, the device can be configured for manual host control, such that the device can monitor
and provide a flag when a protection alert or fault has occurred, but will rely on the host to disable FETs.
The host processor can interface with the BQ76952 device through a serial bus as well as selected pin controls.
Serial bus communication through I
serial bus configured for I
for other versions of the device. The pin controls available include RST_SHUT, ALERT, CFETOFF, DFETOFF,
DDSG, and DCHG, which are described in detail below.
12.5 Multifunction Pin Controls
The BQ76952 device provides flexibility regarding the multifunction pins on the device, which includes the TS1,
TS2, TS3, CFETOFF, DFETOFF, ALERT, HDQ, DCHG, and DDSG pins. Several of the pins can be used as
active-high outputs with configurable output level. The digital output driver for these pins can be configured
to drive an output powered from the REG1 LDO or from the internal REG18 LDO, and thus when asserted
active-high will drive out the voltage of the selected LDO.
The REG18 LDO is not capable of driving high current levels, so it is recommended to only use this
LDO to provide a digital output if it will be driving a very high resistance (such as > 1 MΩ) or light
capacitive load. Otherwise, the REG1 should be powered and used to drive the output signal.
The options supported on each pin include:
ALERT
Alarm interrupt output
HDQ communications
CFETOFF
Input to control the CHG FET (that is, CFETOFF functionality)
DFETOFF
Input to control the DSG FET (that is, DFETOFF functionality)
Input to control both the DSG and CHG FETs (that is, BOTHOFF functionality)
HDQ
HDQ communications
Copyright © 2021 Texas Instruments Incorporated
2
C (supporting speeds up to 400 kHz), SPI or HDQ is available, with the
2
C by default in the BQ76952, while the default communications mode may differ
Product Folder Links:
SLUSE13A – JANUARY 2020 – REVISED MAY 2021
Note
BQ76952
BQ76952
Submit Document Feedback
47
Advertisement
Table of Contents
